Kanika sits nervous in the waiting room of a children’s hospital in Bangalore, where her 9-year-old son is being treated for dengue. “This is the second time he has had dengue, and this time it is more serious. This time, his platelet count has dropped so low that we had to admit it,” he told FIT.
Kanika’s son is one of the many young people with dengue recently admitted to the hospital.
In addition, the first death related to dengue in the town this year was registered on Saturday, June 29.
As the sizzling heat provides monsoons across the country, like clockwork, the season for vector-borne diseases, especially dengue, is also coming to the country, year after year.
Why, then, is the spread of dengue in India so complicated?
Lucknow: Patients undergoing treatment at the dengue ward of Balrampur Hospital in Lucknow in 2022.
(Photo: IANS)
First, let’s take a look at the trajectory of dengue cases in India in recent years.
“Dengue is endemic in India,” says Dr PS Indu, professor and head of network medicine branch, Government Medical College, Kollam, Kerala. This means that the disease is detected in this area and the number of cases has stagnated.
With the exception of 2020, when the COVID-19 pandemic peaked, dengue cases have increased in some parts of the country each year. Peaks often occur between July and September, when most of the country experiences heavy rainfall.
The most recent data from the National Centre for Vector-Borne Disease Control suggests that the total number of annual cases in India has been particularly high since the pandemic compared to pre-COVID-19 years.
Data source: National Center for Vector-Borne Disease Control and Ministry of Health and Social Welfare.
Also, according to government data, some states like Karnataka, Delhi, Kerala, Sikkim and Haryana tend to see the highest cases every year.
Speaking to FIT, Dr. Suneet Verma, Panchkula’s in-house medical specialist, says dengue is largely underreported and the actual number of cases is likely much higher.
“This is the case only in India, but also in neighbouring countries such as Pakistan, Sri Lanka, Thailand and Bangladesh. We are seeing a considerable increase in dengue cases everywhere,” he explains.
Although the dengue virus is well studied, the nature of the virus and the way it spreads make it difficult to contain, experts say. There are a few main points that contribute to this.
Various serotypes
Firstly, there are 4 known serotypes of dengue virus (DEN-1, DEN-2, DEN-3 and DEN-4).
Dr Indu, who led a joint Kerala-World Health Organisation (WHO) study on dengue in India earlier this year, explains that people infected with one serotype develop an antibody reaction against that serotype. serotype.
However, he says, “people can become inflamed again with some other serotype, which triggers an immune reaction and leads to severe dengue. “
In addition to this, Dr Verma says: “Researchers have even discovered evidence of some other fifth serotype, which is not well documented and no control can be done on it. “
The virus may be in the eggs of moqsuitoes.
According to Dr. Srinivasa Rao Mutheneni, a scientist in the department of biology at the CSIR-Indian Institute of Chemical Technology in Hyderabad, “Aedes aegypti and Aedes albopictus mosquitoes are very adaptable and can reproduce in the environment. “
He explains,
They can also be very stubborn, Dr. Indu adds. “It is not enough to drain state water. Mosquito eggs can stick to the surfaces of dry buckets and garage sets with water even after draining. They will have to be scrubbed and cleaned to avoid additional reproduction. Humans rarely do. “
Asymptomatic cases
Another special feature of the dengue virus is that the most inflamed people do not have any symptoms.
It is more difficult to get involved in cases where other people do not even know that they are dengue positive and may simply spread the virus.
According to a recent modeling study in India, approximately 84% of network transmission of dengue occurs in asymptomatic cases.
Speeding and poor planning
According to experts, immediate and unplanned urbanization also favors the creation of many possible breeding habitats for mosquitoes.
Overcrowded cities with insufficient infrastructure and sanitation lead to poor sewage management, flooding and stagnant water (especially in structures), says Dr. Mutheneni.
In addition, due to the lack of water in cities, especially during monsoons, other people tend to store large amounts of water in and around their homes in boxes that are left open or unattended, further increasing the risk of mosquito breeding.
Climate change
“The expansion and life cycle of Aedes mosquitoes are affected by climatic factors such as temperature, precipitation, humidity and wind speed, etc. ,” says Dr. Mutheneni. “Rising temperatures accelerate the progression of Aedes mosquitoes from eggs to adults, leading to faster reproductive cycles. “
He adds: “Climate change can lead to increased migration and displacement due to extreme weather events that introduce the dengue virus into new spaces and facilitate its spread. “
CYD-TDV (Dengvaxia) is the first dengue vaccine licensed and approved for use through the European Medical Association, the US Food and Drug Administration, and some Asian countries, in addition to India. It is also on the WHO list of medicines.
However, for experts, it has its limitations.
The explanation for why this occurs is the complex immune reaction triggered by the dengue virus. This is also the reason why a user develops a more serious illness if he becomes naturally inflamed with dengue more than once.
This makes vaccination formulas more confusing and expensive, as they require a reliable pre-screening formula to detect past infections.
According to Dr. Verma, the immune mechanism of dengue is very complex, which makes it difficult to create a vaccine. He explains: “This is the explanation why we have not scaled up a vaccine for mass use. “
Lately, there are other dengue vaccines that have been approved or are in complex stages of expansion, and the purpose is to expand an effective dengue vaccine that can be included in vaccination systems worldwide, that is, in spaces where dengue is endemic, experts say. .
According to Dr Verma, “Once an outbreak starts, you have to fight it. There is no treatment. We can only provide symptomatic support. Every year we see other young people dying in hospitals because of this. “
For this reason, according to Dr Verma, dengue cannot be targeted specifically unless broader public health problems such as poor sanitation, water scarcity and poor wastewater control are addressed. unsolved.
“Many dengue-prone areas are in low- and middle-income countries with limited vector resources and poor infrastructure capacity to manage outbreaks well,” says Dr. Mutheneni.
In addition, he adds that poor surveillance systems are to blame for the delay in detecting outbreaks and implementing measures.
Dr Indu adds, “Currently, we want to adopt an incorporated vector-targeted technique through network involvement and meticulous clinical monitoring to reduce mortality. »
However, according to Dr. Verma, “so far, the government and fitness have not been proactive in preventing the disease at the network level. “
(At The Quint, we are accountable to our audience. Take an active role in shaping our journalism by onboarding a member. Because the fact is worth it).
Let us first take a look at the trajectory of dengue cases in India in recent years.
“Dengue is endemic in India,” says Dr. P. S. Indu, Professor and Head of the Department of Community Medicine at Kollam Government Faculty of Medicine, Kerala. This means that the disease is detected in this area and the number of cases has stagnated.
With the exception of 2020, when the COVID-19 pandemic peaked, dengue cases have increased in some parts of the country each year. Peaks often occur between July and September, when most of the country experiences heavy rainfall.
The most recent data from the National Centre for Vector-Borne Disease Control suggests that the total number of annual cases in India has been particularly high since the pandemic compared to pre-COVID-19 years.
Data source: National Center for Vector-Borne Disease Control and Ministry of Health and Welfare.
Also, according to government data, some states like Karnataka, Delhi, Kerala, Sikkim, and Haryana tend to enjoy the highest instances every year.
Speaking to FIT, Dr Suneet Verma, internal medical specialist, Panchkula, says dengue is largely underreported and the actual number of cases is most likely much higher.
“This is the case only in India, but also in neighbouring countries such as Pakistan, Sri Lanka, Thailand and Bangladesh. We are seeing a massive increase in dengue cases everywhere,” he said.
Although the dengue virus is well studied, the nature of the virus and how it spreads make it difficult to contain, experts say. There are a few main points that contribute to this.
Various serotypes
First, there are 4 known serotypes of dengue virus (DEN-1, DEN-2, DEN-3, and DEN-4).
Dr Indu, who led a joint Kerala-World Health Organisation (WHO) study on dengue in India earlier this year, explains that people infected with one serotype develop an antibody reaction against that serotype. serotype.
However, he says, “people can become re-inflamed with some other serotype, triggering an immune reaction and leading to severe dengue. “
In addition to this, Dr. Verma says, “Researchers have even discovered evidence of some other fifth serotype, which is not well documented and no control can be done on it. “
The virus can be in the eggs of the Moqsuitoes.
According to Dr. Srinivasa Rao Mutheneni, a scientist in the Division of Biology at the CSIR-Indian Institute of Chemical Technology in Hyderabad, “Aedes aegypti and Aedes albopictus mosquitoes are highly adaptable and can breed in a variety of environments. “
He explains,
They can also be very stubborn, Dr. Indu adds. “It is not enough to empty the stagnant water. Mosquito eggs can stick to the surfaces of dry buckets and garage games with water even after they have been emptied. They want to be scrubbed and cleaned to save your replica that humans rarely do. “
Asymptomatic cases
Another special characteristic of the dengue virus is that the most inflamed people do not present any symptoms.
It’s more complicated to involve cases where other people don’t even know they’re positive for dengue and can just spread the virus.
According to recent modeling in India, approximately 84% of online dengue transmission occurs through asymptomatic cases.
Speeding up and poor planning
According to experts, immediate and unplanned urbanization also favors the creation of many possible breeding habitats for mosquitoes.
Overcrowded cities with insufficient infrastructure and sanitation lead to poor wastewater management, waterlogging and stagnant water (especially in structures), says Dr Mutheneni.
In addition, due to the lack of water in cities, especially during monsoons, other people tend to store large amounts of water in and around their homes in boxes that are left open or unprotected, further increasing the risk of mosquito breeding. .
Climate change
“The expansion and life cycle of Aedes mosquitoes are affected by climatic factors such as temperature, precipitation, humidity and wind speed, etc. ,” says Dr. Mutheneni. “Rising temperatures accelerate the progression of Aedes mosquitoes from eggs to adults, leading to faster reproductive cycles. “
And he adds: “Climate change can cause greater migration and displacement due to extreme weather events that introduce the dengue virus into new spaces and facilitate its spread. “
CYD-TDV (Dengvaxia) is the first dengue vaccine authorized and approved for use through the European Medical Association, the United States Food and Drug Administration, and some Asian countries, in addition to India. It is also on the WHO list of medicines.
However, experts say, this has its limits.
The explanation for why this happens is the complex immune reaction triggered by the dengue virus. This is also why a user develops a more severe disease if it is naturally inflamed by dengue more than once.
This makes vaccination formulas more confusing and expensive, as they require a reliable pre-screening formula to detect past infection.
According to Dr. Verma, the immune mechanism of dengue is very complex, making it difficult to create a vaccine. He explains: “This is the explanation for why we have not expanded a vaccine for mass use. “
Lately, there are other dengue vaccines that have been approved or are in complex stages of expansion, and the purpose is to expand an effective dengue vaccine that can be included in vaccination systems worldwide, that is, in spaces where dengue is endemic, experts say. .
According to Dr Verma, “Once an outbreak starts, you cannot deal with it. There is no treatment. We can only provide symptomatic support. Every year we see other young people dying in hospitals because of this. “
For this reason, according to Dr Verma, dengue cannot be targeted specifically unless broader public health problems such as poor sanitation, water scarcity and poor wastewater control are addressed. unsolved.
“Many dengue-prone spaces are in low- and middle-income countries with limited vector resources and poor fitness infrastructure to manage outbreaks well,” says Dr. Mutheneni.
In addition, he adds that poor surveillance systems are to blame for the delay in detecting outbreaks and implementing measures.
Dr. Indu adds, “Today, we want to adopt a built-in vector-targeting technique through network involvement and meticulous clinical monitoring to reduce mortality. »
However, according to Dr. Verma, “so far, government and fitness services have been proactive in preventing the disease at the network level. “
(At The Quint, we are accountable to our audience. We play an active role in shaping our journalism by adding a member. Because the fact is worth it. )
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